Fuel composition



United States Patent and particularly the petroleum distillate fuels, are largely dependent upon their composition and the conditions to which they are subjected prior to energy-release through combustion in a combustion zone. Compositionwise, the

deposit-forming tendencies or instability of the fuel, are: usually associated with the presence ofthermallyv and/or catalytically cracked components in the fuel and become increasingly pronounced in the higher boiling range fuels. However, in addition to the effect of the organic components of the fuel, certain conditions of storage, transportation and service prior to combustion also contribute materially to the deposit-forming tendencies of the fuel. These conditions are generally conditions of oxidation and result in the formation of soluble and insoluble oxidation products which form the bulk of the deposits laid down on the various metal and other surfaces within the fuel system. Additionally, the presence of nonhydrocarbon contaminants in the fuel, and particularly metals such. as copper and iron, accelerates the oxidative reactions and coincident deposit formation.

The more general oxidative deterioration is obtained as a low temperature oxidation during storage in the presence of air, and the resulting deposit formation is substantially dependent upon the composition or stability of the fuel. Other types of oxidative conditions which, in addition promote deposit formation are encountered in the conditions and fuel systems specific to the various types of hydrocarbon fuels. Thus, in the operation of internal combustion engines, whether compression-ignition or spark-ignition, deposit formation is encountered within the induction system and particularly at the intake valves, injector nozzles, and injection plungers. At the areas of deposit formation, the hydrocarbon fuel is subjected to comparatively high temperatures and comes in contact with combustion and exhaust gases containing oxidation precursors, etc. Another illustration of specific deposit formation of hydrocarbon fuels is in the operation ofaircraft gas turbine engines wherein the fuel may be employed as a coolant and in heat exchange with the circulating lubricating oil. In such situations, the fuel is subjected to skin temperatures of up to 500 F;.and results in the deposition of coke-like deposits on the heat exchanger surfaces.

Athough certain of these deposit-forming tendencies of the hydrocarbon distillate fuels may be eliminated or minimized by additional refinery processing designedto extract, alter, and/or remove the oxidation-sensitive and/or unstable components of the fuel, such practices greatly depreciate the yield of fuel and materially increase the unit fuel costs. However, contrasting the disadvantages of additional process refining of the distillate fuels, it has now been discovered that hydrocarbon fuels may be stabilized against objectionable deposit formation prior According to the present invention itv has :beenfo'und' that the incorporation in a hydrocarbon fuel, and prefer- 'PatntedMar. 1,1930

2 ably a petroleum hydrocarbon distillate fuel, of a minor amount of a specific class of relatively high molecular. weight copolymer compositions will efiect a material re. duction in the formation of insoluble sludges, etc., which may be precipitated or carried with the fuel toform deposits within the fuel system and thereby reduce the:

operating efficiency of the combustion engine or burner. The class of copolymer compositions which have'been determined to be unique in the improving characteristics as described above may be defined as a relatively high molecular Weight copolymer which may be obtained by' the copolymerization of (A) at least one compound con-'- taining an ethylenic linkage and 8 to 30 aliphatic carbon atoms which is copolymerizable through the ethylenic linkage and (B) at least one a,fi-unsaturated aliphatic monocarboxylic acid containing from 3 to 8 carbon atoms, which copolymer is so constituted that at least one of the carboxyl groups of component (B) is present in the form of an ester of a polyalkylene glycol or alkyl ether thereof having from 2 to 7 carbon atoms in each alkylene group and an average molecular weight in excess of 800, said (A) component constituting from about 35 to 99.9 mol percent of the polymer composition.

The polymeric additives of the present invention may: also be more particularly defined as oil-soluble oopolymers' of monomers selected from at least each of the first two classes of the classes consisting of (A) oil-solubilizing compounds having a polymerizable ethylenic linkage and containing a'hydrocarbon group of from 8 to 30 aliphatic carbon atoms, (B) esters of a,B-unsaturated monocarboxylic acids of from 3 to 8 carbon atoms each wherein the carboxyl groups of said acids are monoester-linked to a member of the group consisting of polyalkylene glycols and alkyl ethers thereof having from 2 to 7 carbon atoms in each alkylene group and average molecular weights of more than 800 and (C) o e-unsaturated monocarboxylic acids of from 3 m8 carbon atoms each, said (A)'com ponent constituting from about 35 to 99.9. mole percent and said (B) and (C) components constituting 'a total of from about to 0.1 mole percent of the polymer composition, there being present at least one monomer of said (B) component.

Within the foregoing definition of the hydrocarbon fuel improving agent, the particular composition chosen for optimumeifectiveness is dependent largely'upon the particular type of hydrocarbon fuel, its composition and the environmental conditions to which the fuel is subjected prior to introduction into a combustion zone. Thus, the specific copolymer composition employed in a motor gasoline for maximum. effectiveness in reducing the intake manifold deposits in a spark-ignitiominternal com-' bustion engine will usuallydiflerchemically within the foregoing classification from the copolymer additives incorporated in a high boiling burner fuel containing high concentrations of cracked gas oil stocks to effect the maximum reduction in clogging'and plugging of filters,

For specific illustration of the effectiveness of these ad dition agents in reducing the deposit-forming tendencies of a hydrocarbon fuel, reference is made to the higher; boiling range fuels, such as the aircraft gas turbine engine fuels, commonly referred to asjet fuels; kerosenef gas oils, and particularly the thermal and catalyticall'y cracked gas oils; compression-ignition, internal combu's tion fuels, such as diesel fuels; and the conventional 72,927,013 I V I 3 burner or furnace oils. Particularly for these types of fugl applications, it is desirable to employ an addition agent within the class of relatively high molecular weight copolymers, which may be produced through copolymerization of (A) at least one compound comprising an' aliphatic (including cycloaliphatic) ester containing 8 to 30 carbon atoms and a copolymerizable ethylenio linkage alpha or beta to the carboxyl group, and (B) at least one copolymerizable compound comprising an u,p-unsaturated aliphatic monocarboxylic acid containing from 3 to 8 carbon atoms, to produce a copolymer composition in which the component (A) is present in the ratio of from about 50 to 99.9 mole percent of the polynier composition and in which 50 to 100% of the carboxyl groups of the component (B) are present in the form of an ester of a poly-1,2-alkylene glycol or alkyl ether thereof having from 1 to 7 carbon atoms in each alkylene group and an average molecular weight between 8 and 12,000.

The above class of addition agents may be described more particularly in terms of (A), (B) and (C) as oilsoluble copolymers of monomers selected from at least each of the first two classes of the classes consisting of (A) oil-solubilizing compounds comprising an aliphatic (including cycloaliphatic) ester having a polymerizable ethylenic linkage alpha or beta to the carboxyl group and containing a hydrocarbon group of from 8 to 30 aliphatic carbon atoms, (B) ester of a,B-unsaturated monocarboxylic acids of from 3 to 8 carbon atoms each wherein the carbpxyl groups of said acids are monoester-linked to a member of the group consisting of poly-1,2-alkylene glycols and alkyl ethers thereof having from 2 to 7 carbon atoms in each alkylene group and average molecular weights between 800 and 12,000 and (C) nap-unsaturated monocarboxylic acids of from 3 to 8 carbon atoms each, said (A) component constituting from about 50 to 99.9 mole percent of the polymer composition and said (B) component constituting from about 50 to 100 mole percent of the balance or remainder of the polymer composition.

The copolymerizable component (A) is primarily employed to impart the required degree of oil solubility to the copolymer composition, and, according to the afore mentioned definitions, includes the following: olefin hydrocarbons and particularly alkenes such as polyisobutylene and dodecene-l, cycloalkenes such as cyclohexene and vinylcyclohexane, and styrenes such as p-octylstyrene and p-t-butylstyrene; olefinic ethers, representative of which are the vinyl ethers such as vinyl n-butyl ether, vinyl Z-ethylhexyl ether, and vinyl p-octylphenyl ether, allyl ethers such as allyl cyclohexyl ether and allyl isobutyl ether, and methallyl ethers, such as methallyl nhexyl ether and methallyl octadecyl ether; organic esters in which the copolymerizable ethylenic linkage is contained in the ester-radical, such as the vinyl, allyl, methallyl and crotyl esters of long-chain aliphatic and cycloaliphatic monobasic acids, illustrative of which are vinyl oleate, vinyl palrnitate, allyl laurate, allyl stearate, allyl ricinoleate, allyl naphthenate, methallyl caproate, methallyl palmitate, crotyl oleate, crotyl naphthenate, o -methylcrotyl palmitate; organic esters in which the copolymerizable ethylenic linkage is contained in the acid portion of the molecule, such as the esters of acrylic, methaciylic, crotonic, maleic, citraconic acids, etc., representative. of which are dodecyl acrylate, dodecyl methacrylate, cyclohexyl methacrylate, decyl vinylacetate, octadecyl isocrotonate, didodecyl maleate, di-Z-ethylhexyl fumarate, didodecyl citraconate, etc. For present purposes, the preferred copolymerizable component (A) is an alkyl ester of an a,fi-unsaturated monocarboxylic acid of from 3 to 8 carbon atoms having an alkyl group of from 8 to 30 carbon atoms with the esters of acrylic and methacrylic acids being even more desirable from the standpoint of availability and the effectiveness of copolymers prepared from them.

The term oil-soluble is employed in this description in its commonly accepted sense and is used particularly to denote a solubility for the copolymers of at least 0.0005 by weight of the polymer in the fuel oil.

The other copolymerizable components identified for convenience either as component (B) or as components (B) and (C) in the two types of description given above are employed for the purpose of supplying the requisite active polar constituents in the copolymer composition. As previously indicated, the fundamental structure of these components consists of a monocarboxylic acid and glycol esters thereof, preferably an aliphatic monocarboxylic acid with a copolymerizable olefinic linkage in the a,;8 position to the carboxyl group. More specifically, the acid of component (B) and components (B) and (C) is preferably selected from the tap-unsaturated aliphatic monocarboxylic acids which contain from 3 to 8 carbon atoms in the molecule. Particularly preferred acids are the acrylic and methacrylic acids with their alkyl-substituted derivatives fallingwithin the scope of the general formula RI Rr-CH=-C 0 on in which R and R are members of the group consisting of hydrogen and alkyl radicals containing from 1 to 3 carbon atoms each.

The final copolymer composition may present up to of the carboxyl groups of the acids of component (B) or components (B) and (C) in the copolymers according to the two descriptions given above in the form of their polyglycol ester derivatives. may be introduced initially into the copolymerization reaction by employing as the (B) monomer or (B) and (C) monomers appropriate mixtures of the monocar boxylic acid derivatives and the free monocarboxylic acid, or the copolymerization may be effected with the monocarboxylic acid monomer and the resulting copolymer reacted with the desired polyglycol in appropriate ratio to effect the desired degree of derivative formation.

The desirability of modifying the basic copolymer structure through the use or by the formation of the carboxylic acid derivatives is primarily dependent upon the environmental conditions to which the compounded hydrocarbon fuel is subjected. In addition to the previous variables in composition of the base fuel and projected service conditions, a further selection of optimum copolymer compositions is predicatedupon the fuel system, e.g., wet or dry fuel system. It has been found that, in general, the modified copolymers in which up to 100%, and preferably from about 50 to 100% of the carboxyl groups of component (B) or components (B) and (C) are presented in the form of their polyglycol esters possess certain performance advantages when employed as an improving agent for hydrocarbon fuels in a wet fuel system. Aside from the improve'd'deposit reduction noted in performance tests in a wet burner fuel system, other collateral improvements, such as corrosion inhibition and improved demulsibility, are attained with proper selection of the copolymer derivatives.

The polyalkylene glycols and alkyl ethers thereof used in the esterification of the copolymeric (B) component of the copolymer additives of the invention contain from 2 to 7 carbon atoms in each alkylene group and have an average molecular weight in excess of 800, as already mentioned. Poly-1,2-alkylene glycols and their alkyl ethers having molecular weights between 800 and about 12,000 are preferred. Such glycols may be obtained by polymerizing 1,2-alkylene oxides or mixtures thereof in the presence of a catalyst and a suitable initiator for the reaction such as water, monohydric alcohol in the case of the allyl ethers, mercaptan and the like. The preparation of polyglycol compounds of this type has been fully described heretofore in US. Patents 2,448,664 and 2,457,139, for example, and, therefore, requires no detailed discussion here.

These derivatives ThepolygIycoI ester of the (B) component of the polymer can also be described as having the general structural formula where R and R as indicated above in connection with the definition of the monocarboxylic acid component, are

hydrogen atoms or C -C alkyl radicals, the -R s are,

1,2-alkylene radicals of 2 to 7 carbon atoms, n is an integer greater than 30 and R is a hydrogen atom or a substituted or unsubstituted hydrocarbon group, the substituent groups here contemplated being the polar groups COOH,

ll o-OR,

OH, NO --SH, NR R or 0 ll CRa where the R s and the R s are hydrogen atoms or hydrocarbon groups. For present purposes, however, a more preferred group of (B) monomer components is made up of those compounds wherein, in the above structural formula, R represents a hydrogen atom, R represents hydrogen or a methyl group, the R s are ethylene or propylene groups, and R is hydrogen or an Polyethylene glycol mixtures having averagemolecular weights of 880, 1000, 1540, 2000 or 8,000.

Poly-1,2-propylene glycol mixtures having average molecular weights of 836, 1025 or 10,000.

In preparing the copolymers of this invention it is important to obtain a final product which is oil-soluble, i.e., which is soluble in the fuel oil employed, to the extent of at least 0.0005% and preferably 0.001 or more by weight. Since the various oil-solubilizing monomer characteristics, preliminary tests are made with the polymeric additive to determine Whether the relative proportion of oil-solubilizing monomer compound in the copolymer is high enough to impart the desired degree of oil-solubility. If the solubility in oil is unduly low, and if there remain uncombined carboxyl groups in the copolymer, the oil-solubility thereof can normally be remedied by esterifying a portion of said carboxyl groups with a higher alcohol, e.g., a C or higher aliphatic alcohol such as n-octanol, 2- ethylhexanol, decanol, dodecanol (lauryl alcohol) or the like.

In general, however, satisfactory oil-solubility, antiseams alkyl methacrylate (e.g., laurylmethacrylate), (B) an;

wear and detergency properties are obtained' with mers wherein the (A), or oil-solubilizing component'constitutes from about 35 to 99.9 mole percent, of the over- I all polymer composition, with the (B) and (C), or polar polyglycol ester and acid monomer components representing a total of from 65 to 0.1 mole percent of the polymer composition, there being in all cases at least one and usually several monomer units of said (B), poly-; glycol ester monomer components in the copolymer. Ex

pressed percentagewise, ofthe total polar monomercontent of the copolymer, the (B), or polyglycol esterconrponent constitutes from to 3 mole percent, while the; (C), or acid component constitutes from 0 to'97 mole, percent. 'By a careful program of exploratory research supported by testing data, preferred ranges can be estab lished within the aforesaid ranges for particular polymers and classes of polymers coming within the scope of this invention. Thus, with copolymers of (A) a higher acrylate or methacrylate of'a polyethylene glycol or a polypropylene glycol, or a monoalkyl ether of said glycols, or mixture of said glycols or glycol ethers, or a polyglycol monoether, where the glycols are-of the molecular weights previously specified for these compounds, and (C acrylic or methacrylic acids, there preferably is employed from 50 to 99.9 mole percent of theoil-solu-. bilizing, (A) component. The balance or polar portion of the polymer, taken on the basis of 100 mole per cent polar. portion, is made up from 50 to 100 mole percent of the (B) component and 50 to 0 mole percent of the (C) component. I i

It has been particularly noted in the preferred application of the subject copolymer improving agents in the higher boiling range fuels, such as those boiling predominantly within the range of from 300 to 700 F., and preferably such fuels as contain appreciable concentrattions of catalytically cracked gas oil stocks, that a certain optimum relationship between the total number of ali-, phatic carbon atoms to polar groups within the molecule appears to exist. Evidence has been obtained that for a given concentration the copolymer compositionscontaining a ratio of aliphatic carbon atoms to polar groups within the range of from 7 to 70 appear to embrace the optimum composition for deposit reduction effectiveness. In determining this apparent balance between' the polar and nonpolar constituents, the aliphatic carbon atoms to be considered are the following: CH CH I in the final copolymer composition, it may be necessary or desirable to employ a mixture of monomers for either 'or both; components (A) and (B); Forexample, it is recognized that certain monomers falling within the scope of the definition of component (A), such asthe allyl esters, allyl ethers, vinyl esters, vinyl ethers, and alkenes, are difiicult to copolymerize with a component (B) and (C) monomer to a greater than 1/1 ratio. However, in the event a ratio, (A) to (B) and (C), greater than 1 is desired, this may be accomplished by employing a mix ture of monomers using as the additional monomer, for example, the acrylate esters, methacrylate esters, and/or;

diesters of maleic, fumaric, citraconic, etc., acids, to re- .The cop lymerization of the monomers of component (A) andcomponent (B) and (C) may be conducted in accordance with the conventional bulk, solution or emulsion methods of polymerization, with or without the presence of a polymerization catalyst or initiator, and the choice of the particular method of preparation will depend largely upon practical considerations and the particular types of monomers to be copolymerized. However, the reaction is preferably effected in the presence of an inert organic solvent, such as benzene, toluene, xylene, or petroleum naphtha, to facilitate control of the reaction and handling of the resulting copolymer. Various conventional types of free radical-liberating initiators or polymerization catalysts may be employed; as, for example, the organic peroxides such as benzoyl peroxide, acetyl peroxide, t-butyl hydroperoxide, or dibenzoyl peroxide; or an azonitrile such as l,l'-azodicyclohexanecarbonitrile or cgoU-azodiisobutyronitrile. In addition, other means for initiating the copolymerization reaction may be employed, such as the use of ultraviolet or gamma radiation, as may be obtained from irradiation with a cobalt 60 source. The Organic catalyst or initiator may be employed in amounts of 0.1 to 10% by weight, and preferably in the range of 0.25 to 2%, which amounts may'be incorporated in increments as the reaction proceeds. The temperature of copolymerization will vary, depending upon the selected monomeric reactants and solvent employed, and may vary from about 75 to 150 C. The copolymers formed may have a wide range of apparent molecular weight, and usually of the order of at least several thousands.

The majority of the desired copo-lymer compositions to be employed as improving agents are substantially miscible in hydrocarbon oils, and may be compounded into additive concentrates of at least 10% by weight, and preferably up to 70% by weight. In the preparation of additive concentrates, the concentration of ccpolymer in the hydrocarbon vehicle, such as toluene, mixed xylenes, kerosene, or other petroleum fractions, may be limited by the tendency toward gel formation, and in such instances it has been found desirable to incorporate a modifying agent or polar solvent, such as dimethyl formamide, tetrahydrofuran, Z-methyltetrahydrofuran, dioxane, cresylic acids, propylene carbonate, etc, which function as solubilizjng agents and cosolvents in the copolymer concentrate. These modifying agents or cosolvents are generally employed in concentrations ranging from 1 to 25% of the concentrate. In addition to the copo-lymer improving agent of this invention, other conventional fuel additives which are compatible with the copolymer improving agent may be incorporated into the concentrate for the purpose of facilitating the handling and blending problems involved in the production of the finished hydrocarbon fuel.

As an illustration of the preparation of representative copolymers of the invention, together with their derivatives, the following examples are presented. It is to be understood, however, that these examples are presented solely for illustration and are not to be construed as limitations of the invention compositions. The proportions, unless otherwise specified, are on a weight basis.

EXAMPLE I 100 g. (0.328 mole) of mixed alkyl methacrylates having an equivalent weight of 305, and consisting of 60 mole percent tridecyl meth'acrylate and 40 mole percent octadecyl methacrylate, 8.5 g. (0.0007 mole) of dodecylcapped polyethylene glycol methacrylate in which the polyethylene glycol has an average molecular weight of about 12,000 and 0.06 g. (0.0007 mole) of glacial methacrylic acid were charged to a reaction flask. 100 g. of benzene and 150 cc. of methylethyl ketone were added. 3.2 cc. of a catalyst solution of g. benzoyl peroxide in 100 cc. of methylethyl ketone was added. The mixture was blanketed with nitrogen and heated to reflux temperature'of 175 to 180 F. and maintained at this temperature for about 24 hours with stirring. At 4. hours 1.8 of

8, catalyst solution was added and at 8 hours another 0.9 cc. of catalyst solution was added. At the end of 24 hours there was added 164 g. of 150 neutral mineral oil.-

The mixture was stripped to 280 F. at 3 mm. mercury pressure to remove the solvents. The product thus obtained was a mineral oil concentrate containing 35% by weight of the copolymer of tridecyl methacrylate, octadecyl methacrylate, dodecyl ether of triheptacontado hekata ethylene glycol (av. mol. wt. 12,000) methacrylate and methacrylic acid in a molar ratio of 281/ 187/ 1 /1.

EXAMPLE II 115.9 g. (0.381 mole) of mixed alkyl methacrylate having an equivalent weight of 305 and containing '60 mole percent tridecyl methacrylate and 40 mole percent octadecyl methacrylate, 21.3 g. (0.005 mole) dodecylcapped polyethylene glycol methacrylate in which the polyethylene glycol has an average molecular weight of approximately 3900 and 0.43 g. (0.005 mole) of glacial" methacrylic acid were charged to a reaction flask. g. of benzene and cc. of methylethyl ketone were added. 3.2 cc. of catalyst solution consisting of 15 g. benzoyl peroxide in 100 cc. of methylethyl ketone was; then added. The mixture was heated under a blanket of nitrogen to reflux temperature of about to F. and maintained at this temperature for'about 24 hours. At 18 hours 1.8 cc. of catalyst solution was added,'and at 22 hours 0.9 cc. of catalyst solution was added. 207 g. of 150 neutral mineral oil was added at the end of the 24 hours, and the mixture was stripped to 280 F. at 3 mm. mercury pressure to remove the solvents. The product was a mineral oil concentrate containing 35 of thecopolymer of tridecyl methacrylate, octadecyl methacrylate, dodecyl ether of octaoctacontaethylene glycol methacrylate and methacrylic acid in a molar ratio" of 46/ 30/ 1/ 1.

EXAMPLE III 207 g. (0.7 mole) of mixed tridecyl methacrylate and octadecyl methacrylate in 60/40 mole ratio, 32 g. (0.017 mole) dodecyl-capped polyethylene glycol (1600 average molecular weight) methacrylate, 1.3 g. (0.015 mole) glacial methacrylic acid, 320 g. benzene, 178 cc. methylethyl ketone and 3.1 cc. of 15% catalyst solution of henzoyl peroxide in benzene were charged to a reaction flask fitted with stirrer, thermometer, reflux condenser, nitrogen inlet and dropping funnel. The flask was placed in a bath at 166 F. blanketed with nitrogen and stirred for 18 hours. 360 g. of 150 neutral mineral oil was added. The mixture was stripped to 300 F. pot temperature at 3 mm. mercury pressure to remove solvents. 600 g. of product were thus obtained consisting of a mineral oil concentrate containing 36% by weight of the copolymer of tridecyl methacrylate, octadecyl methacrylate, dodecyl ether of hexatricontaethylene glycolmethacrylate' and methacrylic acid in a molar ratio of 30/20/1/1.

EXAMPLE 1V Into a reaction flask of the type described above were charged 60 g. (0.224 mole) tridecyl meth acrylate, 49 g. (0.145 mole) octadecyl methacrylate, 22 g. (0.052 mole) dodecyl-capped polyethylene glycol (3900 average molecular weight) methacrylate, 126 g. mixed hexanes and 189 g. methylethyl ketone. 3.2 cc. of 15 catalyst solution of benzoyl peroxide in methylethyl ketone was added. The mixture was refluxed at 158 F. for 24 hours with catalyst solution additions of 1.8 cc. at 13 hours and 3.2 cc. at 22 hours. g. of 150 neutral mineral oil was then added. The mixture was stripped to 270 F. at 1,0- mm. mercury pressure to remove solvents. The yield was 326 g. of mineral oil concentrate containing 40% by weight of the copolymer of tridecyl methacrylate, octa decyl methacrylate and dodecyl ether of octaoctaconten. ethylene glycol methacrylate in approximately 46/30/17 molar ratio.

To ascertain the merits of, the copolymer compositioiis of this invention and particularly their merits with regard to deposit reduction in unstable, high boiling fuels such as those as contain appreciable concentrations of cracked oils, a test procedure was established which has been determined to correlate with actual service conditions. This test, briefly described, involves the determination of the filter residue 01'] the amount of insoluble solids of filter plugging dimensions which form in distillate fuels during aging.

The filter residue of a fuel on aging is determined by filtering tests in which a 500 ml. sample of the fuel to be tested is first passed through filter paper into an unstoppered, 1 quart bottle where the filtered sample is stored and aged at 140 F. for four weeks. In an alternative, accelerated aging procedure, the filtered fuel is heated at a temperature .of 212 F. while oxygen is bubbled through it for a period of 6 hours. At the termination of the aging process, the filter residue of the sample is determined by filtering it through a weighed Gooch crucible. with an asbestos mat. hering to the container is dissolved in mlJof /20 benzene-alcohol solution. The gums in this solution are precipitated by the addition of 500 ml. of petroleum ether and the mixture is also filtered through the Gooch crucible. The crucible is then washed with 500 ml.of'

petroleum ether, dried in an oven at 190? F., cooled in a constant'humidity vessel and weighed. The filterr'esi-l agents of the'invention'prepared as described above. In"

these tests the base fuels employed were all 50/50 blends 'of a raw Thermofor catalytically cracked gas oil and a straight run gas oil blended to meet the US. commercial I standards specification of a No. 2 fuel oil. The copoly mer-improving agents were incorporated in base fuels (A) and (B) inconcentrations of 50 ppm, while in base'fuel (C) the concentration was 'p.p.m.

The areas Table 1 Ratio of Filter Residue Filter Residue (1) Monomer to Formed Formed Polymer Additivem Fuel 011 (2) Monomerto During 6-Hour During 4-week (3) Monomer, Oz Blow Test Aging at Etc. at 212 F., F., p.p.m.

p.p.m.

Nona-Base Fuel (A) alone 82 203 Copolymer of (1) trldecyl methacrylate, (2) oetadecyl methacrylate and (3) dodecyl ether of decaethylene glycol (av. mol. wt. 440) metbacrylate in base fuel (A) 5. 7/3. 8/1 60 .192 D 6 6/4.4/1 201 D 7. 5/5/1 183 Do 1218/1 50 179 Oopoly-mer of (1) tridecyl methacrylate, (2) octadecyl methecrylate and (3) dodecyl ether of octadeca ethylene glycol (av. mol. wt. 780) methacrylate in base fuel (A) 9/6/1 33' 56 10.516.5/1 Copolymer of (1) trideeyl methacrylate, (2) octadecyl methacrylate and (3) octadeeyl ether of eicosaethyleue glycol (av. mol. wt. 880) methacrylate in base fuel 13, 2/8. 8/1 103 Copolymer of (1) tridecyl methacrylate, (2) octadecyl methacrylate and (3) dodecyl ether of hexatrlcontaethylene glycol (av. mol. wt. 1,600) methacrylate in base fuel (A)--. 15. 6/10. 3/1 21 56 D 19. 1/12. 7/1 5 Dn 24/16/1 31 30/ 38 Copolymer of (1) trldecyl methacrylate, (2) octadecyl A V methacrylate and (3) dodecyl ether of oetaoctacontaethylene glycol (av. mol. wt. 3,900) methacrylate in base 7 fuel (A) 24/16/1 0 7 D 39. 1/26. 3/1 0 D 45. 6/30. 4/1 1 0 Dn 52.8/35.2l1 0 Oopolymer of (1) trrdecyl methacrylate, (2) octadecyl methacrylate and (3) dodecyl ether of dooctacontahekataethylene glycol (av. mol. wt. 8,000) methacrylate in base fuel A 132/8811 V 0 r o Copolymer of (1) tridecyl methacrylate, (2), oetadecyl methacrylate and (3) dodecyl ether of trlheptacontadohekataethylene glycol (av. mol. wt. 12,000) methacrylate inbase fuel (A 281/187/1 q. 0 o None-Base Fuel (B) alone 101 Copolymer of (1) tridecyl methacrylate, (2) octadecyl methacrylate, (3) dodecyl ether of trlheptacontadohekataethylene glycol (av. mol. wt. 12,000) methacrylate and (4) methaerylic acid in base fuel (B0) 231/187/1/1 30 Oopolymer of (1) trideeyl metbacrylate, (2) octadeeyl methacrylate, (3) dodeeyl ether of octaoctacontaethyleue v glycol.(av. mol. wt. 3,900) methacrylate and (4) meth- I acrylic acid in base fuel (B) 45, 6/30. 4/111 0 Copolymer of (1) tridecyl methacrylate, (2) octadecyl methacrylate, (3) dodecyl ether of octadecaethylene glycol (av. mol. wt. 780) methacrylate and (4) methacrylie acid in base fuel (B) 90/60/10/1 102 Copolymer of (1) tridecyl methacrylate, (2) octadecyl methacrylate and (3) dodecyl ether of octaoctacontaethylene glycol (av. mol. wt. 3,900) methacrylate in base fuel (B). 46/30/1 0 Copolymer of (1) tridecyl methacrylate, (2) octadecyl methacrylate, (3) dodecyl ether of hexatrlcontaethyleue glycol (av. mol. wt. 1,600) methacrylate and (4) metha: cryllc acid in base fuel (B) 30/20/1/1 a 0, NoneBase Fuel (0) l n 153 Copol er of (1) tridecyl methacrylate, (2) o'ctadecyl met acrylate and (3) dodeeyl ether of oetaoctacontaethylene glycol (av. mol. wt. 3,900) methacrylate in base fuel (0). 24/16/1 4 D 45.6/30. 4/1 .........e. 3 Dn 39. 2/26. 2/1 3 Copolymer of (1) tndecyl methacrylate, (2) octadecyl methacrylate and (3) dodecyl ether of hexatricontaethylene glycol (av. mol. wt. 1,600) methacrylate in base fuel (0). 24/16/1 45 Do 19. 1/12. 7/1 38 D 15. 6/10. 8/1 .54 D 1 30/20/1 15 Copolymer of (1) tridecyl methacrylate, (2) octadecyl I methacrylate and (3) dodecyl ether of decaethyle'ne' glycol (av. mol. wt. 440) methacrylate in base fuel (3)-.--- 5. 7/3. 8/1

D w V 7.5/5/1 '133 D 1218/1 I 163 The etfectiveness of the fuel oil compositions of the invention employing the combination of a conventional metal deactivator was also illustrated by the filter residue test results given in Table II which follows. In these prising a major ortionof a liqui hy r car on distil late fuel boiling predominantly above about 300 F, hav ing incorporated therein 0.0005 to 1.0% by weight'of an oil-soluble copolymer of monomers selected {pom at;

tests the base fuel (A) was the same as described 111 least each of the first two classes of the classes consistconnection with the test results of Table I above but ing of (A) alkyl esters of c p-unsaturated monocarboxyllc' included a metal deactivator, dlsalicylal-l,2-propylened1- acids of from 3 to 8 carbon atoms each 111 which the amine, which was employed in a concentration of 4 alkyl groups contain from 8 to carbon atoms each,' p.p.m. The copolymer rmprovmg agents were incor- (B) esters of a o-unsaturated allphatic monocarboxylic" porated 1n the base fuels n concentrations of 23 p.p.m. 10 acids of from 3 to 8 carbon atoms each wherein the Table II Ratio of Filter Residue Filter Residue (1) Monomer to Formed Formed Polymer Additive in Fuel 011 (2) Monomer to During 6-Hour During 4-week (3) Monomer, O2 Blow Test Aging at Etc. at; 212 F., 140 F., p.p.m..

p.p.m.

None-Base Fuel (A) alone 40 123 Copolymer of (1) tridecyl methacrylate, (2) octadecyl methacrylate and (3) dodecyl ether of decaethylene glycol (av. mol. wt. 440) methacrylate in base tuel (AL.-- 5. 7/3.8/1 35 126 0 7. 5/5/1 129 D 12/8/1 35 12a Copolymer of (1) tridecyl methacrylate, (2) octadecyl methacrylate and (3) dodeeyl ether of octadeca ethylene glycol (av. mol. wt. 780) methacrylate in base fuel (A) 9/6/1 30 86 130.. 10. 5/6. 5/1 115 Copolymer of (1) tridecyl methacrylate, (2) octadeeyl methacrylate and (3) octadecyl ether of eicosaethylene glycol (av. mol. wt. 880) methaerylate in base fuel (A) 13. 2/8.8/1 87 Copolymer of (1) tridecyl methacrylate, (2) octadecyl methacrylate and (3) dodecyl ether of hexatricontaethylene glycol (av. mol. wt. 1,600) methacrylate in base fuel (A) 15. 6/10. 3/1 15 43 D0 19. 1/12. 7/1 47 Do 24/16/1 15 48 Qopolymer of (1) tridecyl methecrylate, (2) octadecyl rnethacrylate and(3) dodccyl ether of octaoctacontaethylene glycol (av. mol. wt. 3,900) methacrylate in base fuel (A) 24/16/1 3 Do 7 39. 1126-, 3/1 2 4 Do 45. 6/40. 4/1 3 7 Do 52. 8/35. 2/1 2 Copol er of (1) tridecyl methacrylate, (2) octadecyl met acrylate and (3) dodecyl ether of dooetacontahekatw ethylene glycol (av. mol. wt. 8000) methacrylate in base fuel (A) 132/88/1 0 9 sufiicient to reduce the deposit-forming characteristics of i said fuel of an oil-soluble wpolymer of monomers selected from at least each of the first two classes of the classes consisting of (A) oil-solubilizing compounds having a single polymerizable ethylenic linkage and containing a monovalent hydrocarbon group of from 8, to 30 aliphatic carbon atoms, (B) esters of a,fi-unsaturated aliphatic monocarboxylic acids of from 3 to 8 carbon atoms each wherein the carboxyl groups of said acids are monoester-linked to a member of the group consisting of poly-1,2-alkylene glycols and alkyl others thereof having from 2 to 7 carbon atoms in each alkylene group and average molecular weights of more than 800 and (C) a,;3-unsaturated monocarboxylic acids of from 3 to 8 carbon atoms each, said (A) component constituting from about 35 to 99.9 mole percent and said (B) and (C) components constituting a total of from about to 0.1 mole percent of the polymer composition, there being present in said (B) and (C) components, on the basis of l00 mole. percent total (B) and (C). polar monomers from 3 to 1-00 mole percent of said (B) component, and from 0-97 mole percent of said (C) component. V V

2. An improved hydrocarbon fuel composition comcarboxyl groups of said acids are monoester-linked to a member of the group consisting of polyalkylene glycols and alkyl ethers thereof having from 2 to 7 carbon atoms in each alkylene group and average molecular weights of between 800 and 12,000 and (C) u,fi-unsaturated monocarboxylic acids of from 3 to 8 carbon atoms each, said (A) component constituting from about 50 to 99.9 mole percent and said (B) and (C) components constituting a total of from about 50 to 0.1 mole percent of the polymer composition, there being present in said (B) and (C) components, on the basis of mole percent total (B) and (C) polar monomers, from 50 to 100 mole percent of said (B) component, and from 0-50 mole percent of said (C) component.

3. An improved hydrocarbon fuel composition comprising a predominant portion of a hydrocarbon fuel composed predominantly of hydrocarbons boiling above 300 F. having incorporated therein 0.0005 to 1.0% by weight of an oil-soluble copolymer of monomers selected from at least each of the first two classes of the classes consisting of (A) alkyl esters of a d-unsaturated monocarboxylic acids of from 3 to 8 carbon atoms each in which the alkyl groups contain from 8 to 30 carbon atoms each, (B) esters of cap-unsaturated aliphatic monocarboxylic acids of from 3 to 8 carbon atoms each wherein the carboxyl groups of said acids are monoesterlinked to a polyethylene glycol having an average molecular weight of between 800 and 12,000 and (C) c p-unsaturated monocarboxylic acids of from 3 to 8 carbon atoms each, said (A) component constituting from about 50 to 99.9 mole percent and said (B) and (C) components constituting a total of from about 50 to 0.1 mole percent of the polymer composition, there being present in said (B) and (C) components, on the basis of 100 mole percent total (B) and (C) polar mers. from 50 to 100 mole percent of said (B) component, and from -50 mole percent of said (C) component.

4. An improved hydrocarbon fuel composition comprising a major portion of a liquid hydrocarbon distillate fuel boiling predominantly above about 300 F. having incorporated therein 0.0005 to 1.0% by weight of an oil-soluble copolymer of monomers selected from at least each of the first two classes of the classes consisting of (A) alkyl methacrylates in which =the alkyl groups contain from 8 to 30 carbon atoms each, (B) esters of methacrylic acid wherein the carboxyl group of said acid is monoester-linked to a polyethylene glycol having an average molecular weight of between 800 and 12,000 and (C) methacrylic acid, said (A) component constituting from about 50 to 99.9 mole percent and said (B) and (C) components constituting a total of from about 50 to 0.1 mole percent of the polymer composition, there being present in said (B) and (C) components, on the basis of 100 mole percent total (B) and (C) polar monomers, from 50 to 100 mole percent of said (B) component, and from 0-50 mole percent of said (C) component.

5. An improved hydrocarbon fuel composition comprising a major portion of a liquid hydrocarbon distillate fuel boiling predominantly above about 300 F. having incorporated therein 0.0005 to 1.0% by weight of an oil-soluble copolymer of (A) alkyl methacrylates in which the alkyl groups contain from 8 to 30 carbon atoms each and (B) esters of methacrylic acid wherein the carboxyl group of said acid is monoester-linked to a polyethylene glycol having an average molecular weight of between 800 and 12,000, said (A) component constituting from about 50 to 99.9 mole percent and said (B) component constituting a total of from about 50 to 0.1 mole percent of the polymer composition.

6. A concentrated adapted to be incorporated in liqum y os e i i a fuels boiling pred minantly above about 300 F in concentrations effective to reduce I the deposit-forming characteristics of said fuels consist- 7 0-50 mole percent of said (C) component.

ing essentially of a hydrocarbon fuel containing from 10 to percent by weight of an oil-soluble copolyniei', of (A) alkyl esters of a,fl-unsaturated monocarboxyllic; acids of from 3 to 8 carbon atoms each in which the; alkyl groups contain from 8 to 30 carbon atoms each} (B) esters of cup-unsaturated aliphatic monocarboxylicj acids of from 3 to 8 carbon atoms each wherein the' carboxyl groups of said acids are monoester-linked to a member of the group consisting of poly-1,2-alkylene glycols and alkyl ethers thereof having from 2 to 7 car 99.9 mole percent and said (B) and (C) components constituting a total of from about 50 to 0.1 mole percent of the polymer composition, there being-present in said (B) and (C) components, on the basis of 'mole percent total (B) and (C) polar monomers, from 50 to 100 mole percent of said (B) component, and

References Cited in the file of this patent UNITED STATES PATENTS 2,189,735 2,366,517 Gleason Jan. 2, 1945 2,370,943 Dietrich Mat. 6, 1945 2,459,737 McNab et al May 10, 1949 72,615,845 Lippincott tit '31. ..L... Get. 28, 1952 2,728,751 Catlin 8t 81. Dec. 27, 1955 2,737,452 Catlin 6t 8.1 Mar. 6,2956

FOREIGN PATENTS -r-f'r-" from Kistler et a1 Feb. 6, 1940 t 

1. AN IMPROVED FUEL COMPOSITION COMPRISING A MAJOR PORTION OF A LIQUID HYDROCARBON DISTILLATE FUEL BOILING PREDOMINANTLY ABOVE ABOUT 300*F AND A MINOR PORTION, SUFFICIENT TO REDUCE THE DEPOSIT-FORMING CHARACTERISTICS OF SAID FUEL OF AN OIL-SOLUBLE COPOLYMER OF MONOMERS SELECTED FROM AT LEAST EACH OF THE FIRST TWO CLASSES OF THE CLASSES CONSISTING OF (A) OIL-SOLUBILIZING COMPOUNDS HAVING A SINGLE POLYMERIZABLE ETHYLENIC LINKAGE AND CONTAINING A MONOVALENT HYDROCARBON GROUP OF FROM 8 TO 30 ALIPHATIC CARBON ATOMS, (B) ESTERS OF A,B-UNSATURATED ALIPHATIC MONOCARBOXYLIC ACIDS OF FROM 3 TO 8 CARBON ATOMS EACH WHEREIN THE CARBOXYL GROUPS OF SAID ACIDS ARE MONOESTER-LINKED TO A MEMBER OF THE GROUP CONSISTING OF POLY-1,2-ALKYLENE GLYCOLS AND ALKYL ETHERS THEREOF HAVING FROM 2 TO 7 CARBON ATOMS IN EACH ALKYLENE GROUP AND AVERAGE MOLECULAR WEIGHTS OF MORE THAN 800 AND (C) A,B-UNSATURATED MONOCARBOXYLIC ACIDS OF FROM 3 TO 8 CARBON ATOMS EACH, SAID (A) COMPONENT CONSTITUTING FROM ABOUT 35 TO 99.9 MOLE PERCENT AND SAID (B) AND (C) COMPONENTS CONSTITUTING A TOTAL OF FROM ABOUT 65 TO 0.1 MOLE PERCENT OF THE POLYMER COMPOSITION, THERE BEING PRESENT IN SAID (B) AND (C) COMPONENTS, ON THE BASIS OF 100 MOLE PERCENT TOTAL (B) AND (C) POLAR MONOMERS FROM 3 TO 100 MOLE PERCENT OF SAID (B) COMPONENT, AND FROM 0-97 MOLE PERCENT OF SAID (C) COMPONENT. 